Made for the US and far less formal than any UK counterpart, US-based Govloop has a Govloop UK community and covers odd but interesting topics such as "how can I negotiate my salary in the public sector?"

For NHS staff and people with a stake in health provision, there are the NHS Networks. These feature greatgroups, such as the NHS Ideas Generator , its mission to "create a hopper
of great ideas based on clinical needs which can be voted on and
progressed in an environment of open innovation and invention."